drivers/net/wireless/rt2x00/rt2x00mac.c - pub/scm/linux/kernel/git/jes/staging - Git at Google

 /*
 	Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
 	<http://rt2x00.serialmonkey.com>

 	This program is free software; you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
 	the Free Software Foundation; either version 2 of the License, or
 	(at your option) any later version.

 	This program is distributed in the hope that it will be useful,
 	but WITHOUT ANY WARRANTY; without even the implied warranty of
 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 	GNU General Public License for more details.

 	You should have received a copy of the GNU General Public License
 	along with this program; if not, write to the
 	Free Software Foundation, Inc.,
 	59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */

 /*
 	Module: rt2x00mac
 	Abstract: rt2x00 generic mac80211 routines.
  */

 #include <linux/kernel.h>
 #include <linux/module.h>

 #include "rt2x00.h"
 #include "rt2x00lib.h"

 static int rt2x00mac_tx_rts_cts(struct rt2x00_dev *rt2x00dev,
 				struct data_queue *queue,
 				struct sk_buff *frag_skb)
 {
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(frag_skb);
 	struct ieee80211_tx_info *rts_info;
 	struct sk_buff *skb;
 	int size;

 	if (tx_info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)
 		size = sizeof(struct ieee80211_cts);
 	else
 		size = sizeof(struct ieee80211_rts);

 	skb = dev_alloc_skb(size + rt2x00dev->hw->extra_tx_headroom);
 	if (!skb) {
 		WARNING(rt2x00dev, "Failed to create RTS/CTS frame.\n");
 		return NETDEV_TX_BUSY;
 	}

 	skb_reserve(skb, rt2x00dev->hw->extra_tx_headroom);
 	skb_put(skb, size);

 	/*
 	 * Copy TX information over from original frame to
 	 * RTS/CTS frame. Note that we set the no encryption flag
 	 * since we don't want this frame to be encrypted.
 	 * RTS frames should be acked, while CTS-to-self frames
 	 * should not. The ready for TX flag is cleared to prevent
 	 * it being automatically send when the descriptor is
 	 * written to the hardware.
 	 */
 	memcpy(skb->cb, frag_skb->cb, sizeof(skb->cb));
 	rts_info = IEEE80211_SKB_CB(skb);
 	rts_info->flags |= IEEE80211_TX_CTL_DO_NOT_ENCRYPT;
 	rts_info->flags &= ~IEEE80211_TX_CTL_USE_RTS_CTS;
 	rts_info->flags &= ~IEEE80211_TX_CTL_USE_CTS_PROTECT;
 	rts_info->flags &= ~IEEE80211_TX_CTL_REQ_TX_STATUS;

 	if (tx_info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)
 		rts_info->flags |= IEEE80211_TX_CTL_NO_ACK;
 	else
 		rts_info->flags &= ~IEEE80211_TX_CTL_NO_ACK;

 	if (tx_info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)
 		ieee80211_ctstoself_get(rt2x00dev->hw, tx_info->control.vif,
 					frag_skb->data, size, tx_info,
 					(struct ieee80211_cts *)(skb->data));
 	else
 		ieee80211_rts_get(rt2x00dev->hw, tx_info->control.vif,
 				  frag_skb->data, size, tx_info,
 				  (struct ieee80211_rts *)(skb->data));

 	if (rt2x00queue_write_tx_frame(queue, skb)) {
 		WARNING(rt2x00dev, "Failed to send RTS/CTS frame.\n");
 		return NETDEV_TX_BUSY;
 	}

 	return NETDEV_TX_OK;
 }

 int rt2x00mac_tx(struct ieee80211_hw *hw, struct sk_buff *skb)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
 	struct ieee80211_hdr *ieee80211hdr = (struct ieee80211_hdr *)skb->data;
 	enum data_queue_qid qid = skb_get_queue_mapping(skb);
 	struct rt2x00_intf *intf = vif_to_intf(tx_info->control.vif);
 	struct data_queue *queue;
 	u16 frame_control;

 	/*
 	 * Mac80211 might be calling this function while we are trying
 	 * to remove the device or perhaps suspending it.
 	 * Note that we can only stop the TX queues inside the TX path
 	 * due to possible race conditions in mac80211.
 	 */
 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags)) {
 		ieee80211_stop_queues(hw);
 		dev_kfree_skb_any(skb);
 		return NETDEV_TX_OK;
 	}

 	/*
 	 * Determine which queue to put packet on.
 	 */
 	if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM &&
 	    test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags))
 		queue = rt2x00queue_get_queue(rt2x00dev, QID_ATIM);
 	else
 		queue = rt2x00queue_get_queue(rt2x00dev, qid);
 	if (unlikely(!queue)) {
 		ERROR(rt2x00dev,
 		      "Attempt to send packet over invalid queue %d.\n"
 		      "Please file bug report to %s.\n", qid, DRV_PROJECT);
 		dev_kfree_skb_any(skb);
 		return NETDEV_TX_OK;
 	}

 	/*
 	 * If CTS/RTS is required. create and queue that frame first.
 	 * Make sure we have at least enough entries available to send
 	 * this CTS/RTS frame as well as the data frame.
 	 * Note that when the driver has set the set_rts_threshold()
 	 * callback function it doesn't need software generation of
 	 * either RTS or CTS-to-self frame and handles everything
 	 * inside the hardware.
 	 */
 	frame_control = le16_to_cpu(ieee80211hdr->frame_control);
 	if ((tx_info->flags & (IEEE80211_TX_CTL_USE_RTS_CTS |
 			       IEEE80211_TX_CTL_USE_CTS_PROTECT)) &&
 	    !rt2x00dev->ops->hw->set_rts_threshold) {
 		if (rt2x00queue_available(queue) <= 1) {
 			ieee80211_stop_queue(rt2x00dev->hw, qid);
 			return NETDEV_TX_BUSY;
 		}

 		if (rt2x00mac_tx_rts_cts(rt2x00dev, queue, skb)) {
 			ieee80211_stop_queue(rt2x00dev->hw, qid);
 			return NETDEV_TX_BUSY;
 		}
 	}

 	/*
 	 * XXX: This is as wrong as the old mac80211 code was,
 	 *	due to beacons not getting sequence numbers assigned
 	 *	properly.
 	 */
 	if (tx_info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ) {
 		if (tx_info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT)
 			intf->seqno += 0x10;
 		ieee80211hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
 		ieee80211hdr->seq_ctrl |= cpu_to_le16(intf->seqno);
 	}

 	if (rt2x00queue_write_tx_frame(queue, skb)) {
 		ieee80211_stop_queue(rt2x00dev->hw, qid);
 		return NETDEV_TX_BUSY;
 	}

 	if (rt2x00queue_threshold(queue))
 		ieee80211_stop_queue(rt2x00dev->hw, qid);

 	return NETDEV_TX_OK;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_tx);

 int rt2x00mac_start(struct ieee80211_hw *hw)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;

 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
 		return 0;

 	return rt2x00lib_start(rt2x00dev);
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_start);

 void rt2x00mac_stop(struct ieee80211_hw *hw)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;

 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
 		return;

 	rt2x00lib_stop(rt2x00dev);
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_stop);

 int rt2x00mac_add_interface(struct ieee80211_hw *hw,
 			    struct ieee80211_if_init_conf *conf)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct rt2x00_intf *intf = vif_to_intf(conf->vif);
 	struct data_queue *queue = rt2x00queue_get_queue(rt2x00dev, QID_BEACON);
 	struct queue_entry *entry = NULL;
 	unsigned int i;

 	/*
 	 * Don't allow interfaces to be added
 	 * the device has disappeared.
 	 */
 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags) ||
 	    !test_bit(DEVICE_STARTED, &rt2x00dev->flags))
 		return -ENODEV;

 	/*
 	 * We don't support mixed combinations of sta and ap virtual
 	 * interfaces. We can only add this interface when the rival
 	 * interface count is 0.
 	 */
 	if ((conf->type == IEEE80211_IF_TYPE_AP && rt2x00dev->intf_sta_count) ||
 	    (conf->type != IEEE80211_IF_TYPE_AP && rt2x00dev->intf_ap_count))
 		return -ENOBUFS;

 	/*
 	 * Check if we exceeded the maximum amount of supported interfaces.
 	 */
 	if ((conf->type == IEEE80211_IF_TYPE_AP &&
 	     rt2x00dev->intf_ap_count >= rt2x00dev->ops->max_ap_intf) ||
 	    (conf->type != IEEE80211_IF_TYPE_AP &&
 	     rt2x00dev->intf_sta_count >= rt2x00dev->ops->max_sta_intf))
 		return -ENOBUFS;

 	/*
 	 * Loop through all beacon queues to find a free
 	 * entry. Since there are as much beacon entries
 	 * as the maximum interfaces, this search shouldn't
 	 * fail.
 	 */
 	for (i = 0; i < queue->limit; i++) {
 		entry = &queue->entries[i];
 		if (!__test_and_set_bit(ENTRY_BCN_ASSIGNED, &entry->flags))
 			break;
 	}

 	if (unlikely(i == queue->limit))
 		return -ENOBUFS;

 	/*
 	 * We are now absolutely sure the interface can be created,
 	 * increase interface count and start initialization.
 	 */

 	if (conf->type == IEEE80211_IF_TYPE_AP)
 		rt2x00dev->intf_ap_count++;
 	else
 		rt2x00dev->intf_sta_count++;

 	spin_lock_init(&intf->lock);
 	intf->beacon = entry;

 	if (conf->type == IEEE80211_IF_TYPE_AP)
 		memcpy(&intf->bssid, conf->mac_addr, ETH_ALEN);
 	memcpy(&intf->mac, conf->mac_addr, ETH_ALEN);

 	/*
 	 * The MAC adddress must be configured after the device
 	 * has been initialized. Otherwise the device can reset
 	 * the MAC registers.
 	 */
 	rt2x00lib_config_intf(rt2x00dev, intf, conf->type, intf->mac, NULL);

 	/*
 	 * Some filters depend on the current working mode. We can force
 	 * an update during the next configure_filter() run by mac80211 by
 	 * resetting the current packet_filter state.
 	 */
 	rt2x00dev->packet_filter = 0;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_add_interface);

 void rt2x00mac_remove_interface(struct ieee80211_hw *hw,
 				struct ieee80211_if_init_conf *conf)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct rt2x00_intf *intf = vif_to_intf(conf->vif);

 	/*
 	 * Don't allow interfaces to be remove while
 	 * either the device has disappeared or when
 	 * no interface is present.
 	 */
 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags) ||
 	    (conf->type == IEEE80211_IF_TYPE_AP && !rt2x00dev->intf_ap_count) ||
 	    (conf->type != IEEE80211_IF_TYPE_AP && !rt2x00dev->intf_sta_count))
 		return;

 	if (conf->type == IEEE80211_IF_TYPE_AP)
 		rt2x00dev->intf_ap_count--;
 	else
 		rt2x00dev->intf_sta_count--;

 	/*
 	 * Release beacon entry so it is available for
 	 * new interfaces again.
 	 */
 	__clear_bit(ENTRY_BCN_ASSIGNED, &intf->beacon->flags);

 	/*
 	 * Make sure the bssid and mac address registers
 	 * are cleared to prevent false ACKing of frames.
 	 */
 	rt2x00lib_config_intf(rt2x00dev, intf,
 			      IEEE80211_IF_TYPE_INVALID, NULL, NULL);
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_remove_interface);

 int rt2x00mac_config(struct ieee80211_hw *hw, struct ieee80211_conf *conf)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;

 	/*
 	 * Mac80211 might be calling this function while we are trying
 	 * to remove the device or perhaps suspending it.
 	 */
 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
 		return 0;

 	/*
 	 * Check if we need to disable the radio,
 	 * if this is not the case, at least the RX must be disabled.
 	 */
 	if (test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags)) {
 		if (!conf->radio_enabled)
 			rt2x00lib_disable_radio(rt2x00dev);
 		else
 			rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_OFF);
 	}

 	rt2x00lib_config(rt2x00dev, conf, 0);

 	/*
 	 * Reenable RX only if the radio should be on.
 	 */
 	if (test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
 		rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_ON);
 	else if (conf->radio_enabled)
 		return rt2x00lib_enable_radio(rt2x00dev);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_config);

 int rt2x00mac_config_interface(struct ieee80211_hw *hw,
 			       struct ieee80211_vif *vif,
 			       struct ieee80211_if_conf *conf)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct rt2x00_intf *intf = vif_to_intf(vif);
 	int update_bssid = 0;
 	int status = 0;

 	/*
 	 * Mac80211 might be calling this function while we are trying
 	 * to remove the device or perhaps suspending it.
 	 */
 	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
 		return 0;

 	spin_lock(&intf->lock);

 	/*
 	 * conf->bssid can be NULL if coming from the internal
 	 * beacon update routine.
 	 */
 	if (conf->changed & IEEE80211_IFCC_BSSID && conf->bssid) {
 		update_bssid = 1;
 		memcpy(&intf->bssid, conf->bssid, ETH_ALEN);
 	}

 	spin_unlock(&intf->lock);

 	/*
 	 * Call rt2x00_config_intf() outside of the spinlock context since
 	 * the call will sleep for USB drivers. By using the ieee80211_if_conf
 	 * values as arguments we make keep access to rt2x00_intf thread safe
 	 * even without the lock.
 	 */
 	rt2x00lib_config_intf(rt2x00dev, intf, vif->type, NULL,
 			      update_bssid ? conf->bssid : NULL);

 	/*
 	 * Update the beacon.
 	 */
 	if (conf->changed & IEEE80211_IFCC_BEACON)
 		status = rt2x00queue_update_beacon(rt2x00dev, vif);

 	return status;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_config_interface);

 void rt2x00mac_configure_filter(struct ieee80211_hw *hw,
 				unsigned int changed_flags,
 				unsigned int *total_flags,
 				int mc_count, struct dev_addr_list *mc_list)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;

 	/*
 	 * Mask off any flags we are going to ignore
 	 * from the total_flags field.
 	 */
 	*total_flags &=
 	    FIF_ALLMULTI |
 	    FIF_FCSFAIL |
 	    FIF_PLCPFAIL |
 	    FIF_CONTROL |
 	    FIF_OTHER_BSS |
 	    FIF_PROMISC_IN_BSS;

 	/*
 	 * Apply some rules to the filters:
 	 * - Some filters imply different filters to be set.
 	 * - Some things we can't filter out at all.
 	 * - Multicast filter seems to kill broadcast traffic so never use it.
 	 */
 	*total_flags |= FIF_ALLMULTI;
 	if (*total_flags & FIF_OTHER_BSS ||
 	    *total_flags & FIF_PROMISC_IN_BSS)
 		*total_flags |= FIF_PROMISC_IN_BSS | FIF_OTHER_BSS;

 	/*
 	 * Check if there is any work left for us.
 	 */
 	if (rt2x00dev->packet_filter == *total_flags)
 		return;
 	rt2x00dev->packet_filter = *total_flags;

 	if (!test_bit(DRIVER_REQUIRE_SCHEDULED, &rt2x00dev->flags))
 		rt2x00dev->ops->lib->config_filter(rt2x00dev, *total_flags);
 	else
 		queue_work(rt2x00dev->hw->workqueue, &rt2x00dev->filter_work);
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_configure_filter);

 int rt2x00mac_get_stats(struct ieee80211_hw *hw,
 			struct ieee80211_low_level_stats *stats)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;

 	/*
 	 * The dot11ACKFailureCount, dot11RTSFailureCount and
 	 * dot11RTSSuccessCount are updated in interrupt time.
 	 * dot11FCSErrorCount is updated in the link tuner.
 	 */
 	memcpy(stats, &rt2x00dev->low_level_stats, sizeof(*stats));

 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_get_stats);

 int rt2x00mac_get_tx_stats(struct ieee80211_hw *hw,
 			   struct ieee80211_tx_queue_stats *stats)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	unsigned int i;

 	for (i = 0; i < rt2x00dev->ops->tx_queues; i++) {
 		stats[i].len = rt2x00dev->tx[i].length;
 		stats[i].limit = rt2x00dev->tx[i].limit;
 		stats[i].count = rt2x00dev->tx[i].count;
 	}

 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_get_tx_stats);

 void rt2x00mac_bss_info_changed(struct ieee80211_hw *hw,
 				struct ieee80211_vif *vif,
 				struct ieee80211_bss_conf *bss_conf,
 				u32 changes)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct rt2x00_intf *intf = vif_to_intf(vif);
 	unsigned int delayed = 0;

 	/*
 	 * When the association status has changed we must reset the link
 	 * tuner counter. This is because some drivers determine if they
 	 * should perform link tuning based on the number of seconds
 	 * while associated or not associated.
 	 */
 	if (changes & BSS_CHANGED_ASSOC) {
 		rt2x00dev->link.count = 0;

 		if (bss_conf->assoc)
 			rt2x00dev->intf_associated++;
 		else
 			rt2x00dev->intf_associated--;

 		if (!test_bit(DRIVER_REQUIRE_SCHEDULED, &rt2x00dev->flags))
 			rt2x00leds_led_assoc(rt2x00dev,
 					     !!rt2x00dev->intf_associated);
 		else
 			delayed |= DELAYED_LED_ASSOC;
 	}

 	/*
 	 * When the erp information has changed, we should perform
 	 * additional configuration steps. For all other changes we are done.
 	 */
 	if (changes & (BSS_CHANGED_ERP_PREAMBLE | BSS_CHANGED_ERP_CTS_PROT)) {
 		if (!test_bit(DRIVER_REQUIRE_SCHEDULED, &rt2x00dev->flags))
 			rt2x00lib_config_erp(rt2x00dev, intf, bss_conf);
 		else
 			delayed |= DELAYED_CONFIG_ERP;
 	}

 	spin_lock(&intf->lock);
 	memcpy(&intf->conf, bss_conf, sizeof(*bss_conf));
 	if (delayed) {
 		intf->delayed_flags |= delayed;
 		schedule_work(&rt2x00dev->intf_work);
 	}
 	spin_unlock(&intf->lock);
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_bss_info_changed);

 int rt2x00mac_conf_tx(struct ieee80211_hw *hw, u16 queue_idx,
 		      const struct ieee80211_tx_queue_params *params)
 {
 	struct rt2x00_dev *rt2x00dev = hw->priv;
 	struct data_queue *queue;

 	queue = rt2x00queue_get_queue(rt2x00dev, queue_idx);
 	if (unlikely(!queue))
 		return -EINVAL;

 	/*
 	 * The passed variables are stored as real value ((2^n)-1).
 	 * Ralink registers require to know the bit number 'n'.
 	 */
 	if (params->cw_min > 0)
 		queue->cw_min = fls(params->cw_min);
 	else
 		queue->cw_min = 5; /* cw_min: 2^5 = 32. */

 	if (params->cw_max > 0)
 		queue->cw_max = fls(params->cw_max);
 	else
 		queue->cw_max = 10; /* cw_min: 2^10 = 1024. */

 	queue->aifs = params->aifs;

 	INFO(rt2x00dev,
 	     "Configured TX queue %d - CWmin: %d, CWmax: %d, Aifs: %d.\n",
 	     queue_idx, queue->cw_min, queue->cw_max, queue->aifs);

 	return 0;
 }
 EXPORT_SYMBOL_GPL(rt2x00mac_conf_tx);
	/*
	Copyright (C) 2004 - 2008 rt2x00 SourceForge Project
	<http://rt2x00.serialmonkey.com>

	This program is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to the
	Free Software Foundation, Inc.,
	59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
	*/

	/*
	Module: rt2x00mac
	Abstract: rt2x00 generic mac80211 routines.
	*/

	#include <linux/kernel.h>
	#include <linux/module.h>

	#include "rt2x00.h"
	#include "rt2x00lib.h"

	static int rt2x00mac_tx_rts_cts(struct rt2x00_dev *rt2x00dev,
	struct data_queue *queue,
	struct sk_buff *frag_skb)
	{
	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(frag_skb);
	struct ieee80211_tx_info *rts_info;
	struct sk_buff *skb;
	int size;

	if (tx_info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)
	size = sizeof(struct ieee80211_cts);
	else
	size = sizeof(struct ieee80211_rts);

	skb = dev_alloc_skb(size + rt2x00dev->hw->extra_tx_headroom);
	if (!skb) {
	WARNING(rt2x00dev, "Failed to create RTS/CTS frame.\n");
	return NETDEV_TX_BUSY;
	}

	skb_reserve(skb, rt2x00dev->hw->extra_tx_headroom);
	skb_put(skb, size);

	/*
	* Copy TX information over from original frame to
	* RTS/CTS frame. Note that we set the no encryption flag
	* since we don't want this frame to be encrypted.
	* RTS frames should be acked, while CTS-to-self frames
	* should not. The ready for TX flag is cleared to prevent
	* it being automatically send when the descriptor is
	* written to the hardware.
	*/
	memcpy(skb->cb, frag_skb->cb, sizeof(skb->cb));
	rts_info = IEEE80211_SKB_CB(skb);
	rts_info->flags \|= IEEE80211_TX_CTL_DO_NOT_ENCRYPT;
	rts_info->flags &= ~IEEE80211_TX_CTL_USE_RTS_CTS;
	rts_info->flags &= ~IEEE80211_TX_CTL_USE_CTS_PROTECT;
	rts_info->flags &= ~IEEE80211_TX_CTL_REQ_TX_STATUS;

	if (tx_info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)
	rts_info->flags \|= IEEE80211_TX_CTL_NO_ACK;
	else
	rts_info->flags &= ~IEEE80211_TX_CTL_NO_ACK;

	if (tx_info->flags & IEEE80211_TX_CTL_USE_CTS_PROTECT)
	ieee80211_ctstoself_get(rt2x00dev->hw, tx_info->control.vif,
	frag_skb->data, size, tx_info,
	(struct ieee80211_cts *)(skb->data));
	else
	ieee80211_rts_get(rt2x00dev->hw, tx_info->control.vif,
	frag_skb->data, size, tx_info,
	(struct ieee80211_rts *)(skb->data));

	if (rt2x00queue_write_tx_frame(queue, skb)) {
	WARNING(rt2x00dev, "Failed to send RTS/CTS frame.\n");
	return NETDEV_TX_BUSY;
	}

	return NETDEV_TX_OK;
	}

	int rt2x00mac_tx(struct ieee80211_hw hw, struct sk_buff skb)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct ieee80211_tx_info *tx_info = IEEE80211_SKB_CB(skb);
	struct ieee80211_hdr ieee80211hdr = (struct ieee80211_hdr )skb->data;
	enum data_queue_qid qid = skb_get_queue_mapping(skb);
	struct rt2x00_intf *intf = vif_to_intf(tx_info->control.vif);
	struct data_queue *queue;
	u16 frame_control;

	/*
	* Mac80211 might be calling this function while we are trying
	* to remove the device or perhaps suspending it.
	* Note that we can only stop the TX queues inside the TX path
	* due to possible race conditions in mac80211.
	*/
	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags)) {
	ieee80211_stop_queues(hw);
	dev_kfree_skb_any(skb);
	return NETDEV_TX_OK;
	}

	/*
	* Determine which queue to put packet on.
	*/
	if (tx_info->flags & IEEE80211_TX_CTL_SEND_AFTER_DTIM &&
	test_bit(DRIVER_REQUIRE_ATIM_QUEUE, &rt2x00dev->flags))
	queue = rt2x00queue_get_queue(rt2x00dev, QID_ATIM);
	else
	queue = rt2x00queue_get_queue(rt2x00dev, qid);
	if (unlikely(!queue)) {
	ERROR(rt2x00dev,
	"Attempt to send packet over invalid queue %d.\n"
	"Please file bug report to %s.\n", qid, DRV_PROJECT);
	dev_kfree_skb_any(skb);
	return NETDEV_TX_OK;
	}

	/*
	* If CTS/RTS is required. create and queue that frame first.
	* Make sure we have at least enough entries available to send
	* this CTS/RTS frame as well as the data frame.
	* Note that when the driver has set the set_rts_threshold()
	* callback function it doesn't need software generation of
	* either RTS or CTS-to-self frame and handles everything
	* inside the hardware.
	*/
	frame_control = le16_to_cpu(ieee80211hdr->frame_control);
	if ((tx_info->flags & (IEEE80211_TX_CTL_USE_RTS_CTS \|
	IEEE80211_TX_CTL_USE_CTS_PROTECT)) &&
	!rt2x00dev->ops->hw->set_rts_threshold) {
	if (rt2x00queue_available(queue) <= 1) {
	ieee80211_stop_queue(rt2x00dev->hw, qid);
	return NETDEV_TX_BUSY;
	}

	if (rt2x00mac_tx_rts_cts(rt2x00dev, queue, skb)) {
	ieee80211_stop_queue(rt2x00dev->hw, qid);
	return NETDEV_TX_BUSY;
	}
	}

	/*
	* XXX: This is as wrong as the old mac80211 code was,
	* due to beacons not getting sequence numbers assigned
	* properly.
	*/
	if (tx_info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ) {
	if (tx_info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT)
	intf->seqno += 0x10;
	ieee80211hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
	ieee80211hdr->seq_ctrl \|= cpu_to_le16(intf->seqno);
	}

	if (rt2x00queue_write_tx_frame(queue, skb)) {
	ieee80211_stop_queue(rt2x00dev->hw, qid);
	return NETDEV_TX_BUSY;
	}

	if (rt2x00queue_threshold(queue))
	ieee80211_stop_queue(rt2x00dev->hw, qid);

	return NETDEV_TX_OK;
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_tx);

	int rt2x00mac_start(struct ieee80211_hw *hw)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;

	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
	return 0;

	return rt2x00lib_start(rt2x00dev);
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_start);

	void rt2x00mac_stop(struct ieee80211_hw *hw)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;

	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
	return;

	rt2x00lib_stop(rt2x00dev);
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_stop);

	int rt2x00mac_add_interface(struct ieee80211_hw *hw,
	struct ieee80211_if_init_conf *conf)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct rt2x00_intf *intf = vif_to_intf(conf->vif);
	struct data_queue *queue = rt2x00queue_get_queue(rt2x00dev, QID_BEACON);
	struct queue_entry *entry = NULL;
	unsigned int i;

	/*
	* Don't allow interfaces to be added
	* the device has disappeared.
	*/
	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags) \|\|
	!test_bit(DEVICE_STARTED, &rt2x00dev->flags))
	return -ENODEV;

	/*
	* We don't support mixed combinations of sta and ap virtual
	* interfaces. We can only add this interface when the rival
	* interface count is 0.
	*/
	if ((conf->type == IEEE80211_IF_TYPE_AP && rt2x00dev->intf_sta_count) \|\|
	(conf->type != IEEE80211_IF_TYPE_AP && rt2x00dev->intf_ap_count))
	return -ENOBUFS;

	/*
	* Check if we exceeded the maximum amount of supported interfaces.
	*/
	if ((conf->type == IEEE80211_IF_TYPE_AP &&
	rt2x00dev->intf_ap_count >= rt2x00dev->ops->max_ap_intf) \|\|
	(conf->type != IEEE80211_IF_TYPE_AP &&
	rt2x00dev->intf_sta_count >= rt2x00dev->ops->max_sta_intf))
	return -ENOBUFS;

	/*
	* Loop through all beacon queues to find a free
	* entry. Since there are as much beacon entries
	* as the maximum interfaces, this search shouldn't
	* fail.
	*/
	for (i = 0; i < queue->limit; i++) {
	entry = &queue->entries[i];
	if (!__test_and_set_bit(ENTRY_BCN_ASSIGNED, &entry->flags))
	break;
	}

	if (unlikely(i == queue->limit))
	return -ENOBUFS;

	/*
	* We are now absolutely sure the interface can be created,
	* increase interface count and start initialization.
	*/

	if (conf->type == IEEE80211_IF_TYPE_AP)
	rt2x00dev->intf_ap_count++;
	else
	rt2x00dev->intf_sta_count++;

	spin_lock_init(&intf->lock);
	intf->beacon = entry;

	if (conf->type == IEEE80211_IF_TYPE_AP)
	memcpy(&intf->bssid, conf->mac_addr, ETH_ALEN);
	memcpy(&intf->mac, conf->mac_addr, ETH_ALEN);

	/*
	* The MAC adddress must be configured after the device
	* has been initialized. Otherwise the device can reset
	* the MAC registers.
	*/
	rt2x00lib_config_intf(rt2x00dev, intf, conf->type, intf->mac, NULL);

	/*
	* Some filters depend on the current working mode. We can force
	* an update during the next configure_filter() run by mac80211 by
	* resetting the current packet_filter state.
	*/
	rt2x00dev->packet_filter = 0;

	return 0;
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_add_interface);

	void rt2x00mac_remove_interface(struct ieee80211_hw *hw,
	struct ieee80211_if_init_conf *conf)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct rt2x00_intf *intf = vif_to_intf(conf->vif);

	/*
	* Don't allow interfaces to be remove while
	* either the device has disappeared or when
	* no interface is present.
	*/
	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags) \|\|
	(conf->type == IEEE80211_IF_TYPE_AP && !rt2x00dev->intf_ap_count) \|\|
	(conf->type != IEEE80211_IF_TYPE_AP && !rt2x00dev->intf_sta_count))
	return;

	if (conf->type == IEEE80211_IF_TYPE_AP)
	rt2x00dev->intf_ap_count--;
	else
	rt2x00dev->intf_sta_count--;

	/*
	* Release beacon entry so it is available for
	* new interfaces again.
	*/
	__clear_bit(ENTRY_BCN_ASSIGNED, &intf->beacon->flags);

	/*
	* Make sure the bssid and mac address registers
	* are cleared to prevent false ACKing of frames.
	*/
	rt2x00lib_config_intf(rt2x00dev, intf,
	IEEE80211_IF_TYPE_INVALID, NULL, NULL);
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_remove_interface);

	int rt2x00mac_config(struct ieee80211_hw hw, struct ieee80211_conf conf)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;

	/*
	* Mac80211 might be calling this function while we are trying
	* to remove the device or perhaps suspending it.
	*/
	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
	return 0;

	/*
	* Check if we need to disable the radio,
	* if this is not the case, at least the RX must be disabled.
	*/
	if (test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags)) {
	if (!conf->radio_enabled)
	rt2x00lib_disable_radio(rt2x00dev);
	else
	rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_OFF);
	}

	rt2x00lib_config(rt2x00dev, conf, 0);

	/*
	* Reenable RX only if the radio should be on.
	*/
	if (test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags))
	rt2x00lib_toggle_rx(rt2x00dev, STATE_RADIO_RX_ON);
	else if (conf->radio_enabled)
	return rt2x00lib_enable_radio(rt2x00dev);

	return 0;
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_config);

	int rt2x00mac_config_interface(struct ieee80211_hw *hw,
	struct ieee80211_vif *vif,
	struct ieee80211_if_conf *conf)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct rt2x00_intf *intf = vif_to_intf(vif);
	int update_bssid = 0;
	int status = 0;

	/*
	* Mac80211 might be calling this function while we are trying
	* to remove the device or perhaps suspending it.
	*/
	if (!test_bit(DEVICE_PRESENT, &rt2x00dev->flags))
	return 0;

	spin_lock(&intf->lock);

	/*
	* conf->bssid can be NULL if coming from the internal
	* beacon update routine.
	*/
	if (conf->changed & IEEE80211_IFCC_BSSID && conf->bssid) {
	update_bssid = 1;
	memcpy(&intf->bssid, conf->bssid, ETH_ALEN);
	}

	spin_unlock(&intf->lock);

	/*
	* Call rt2x00_config_intf() outside of the spinlock context since
	* the call will sleep for USB drivers. By using the ieee80211_if_conf
	* values as arguments we make keep access to rt2x00_intf thread safe
	* even without the lock.
	*/
	rt2x00lib_config_intf(rt2x00dev, intf, vif->type, NULL,
	update_bssid ? conf->bssid : NULL);

	/*
	* Update the beacon.
	*/
	if (conf->changed & IEEE80211_IFCC_BEACON)
	status = rt2x00queue_update_beacon(rt2x00dev, vif);

	return status;
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_config_interface);

	void rt2x00mac_configure_filter(struct ieee80211_hw *hw,
	unsigned int changed_flags,
	unsigned int *total_flags,
	int mc_count, struct dev_addr_list *mc_list)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;

	/*
	* Mask off any flags we are going to ignore
	* from the total_flags field.
	*/
	*total_flags &=
	FIF_ALLMULTI \|
	FIF_FCSFAIL \|
	FIF_PLCPFAIL \|
	FIF_CONTROL \|
	FIF_OTHER_BSS \|
	FIF_PROMISC_IN_BSS;

	/*
	* Apply some rules to the filters:
	* - Some filters imply different filters to be set.
	* - Some things we can't filter out at all.
	* - Multicast filter seems to kill broadcast traffic so never use it.
	*/
	*total_flags \|= FIF_ALLMULTI;
	if (*total_flags & FIF_OTHER_BSS \|\|
	*total_flags & FIF_PROMISC_IN_BSS)
	*total_flags \|= FIF_PROMISC_IN_BSS \| FIF_OTHER_BSS;

	/*
	* Check if there is any work left for us.
	*/
	if (rt2x00dev->packet_filter == *total_flags)
	return;
	rt2x00dev->packet_filter = *total_flags;

	if (!test_bit(DRIVER_REQUIRE_SCHEDULED, &rt2x00dev->flags))
	rt2x00dev->ops->lib->config_filter(rt2x00dev, *total_flags);
	else
	queue_work(rt2x00dev->hw->workqueue, &rt2x00dev->filter_work);
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_configure_filter);

	int rt2x00mac_get_stats(struct ieee80211_hw *hw,
	struct ieee80211_low_level_stats *stats)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;

	/*
	* The dot11ACKFailureCount, dot11RTSFailureCount and
	* dot11RTSSuccessCount are updated in interrupt time.
	* dot11FCSErrorCount is updated in the link tuner.
	*/
	memcpy(stats, &rt2x00dev->low_level_stats, sizeof(*stats));

	return 0;
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_get_stats);

	int rt2x00mac_get_tx_stats(struct ieee80211_hw *hw,
	struct ieee80211_tx_queue_stats *stats)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	unsigned int i;

	for (i = 0; i < rt2x00dev->ops->tx_queues; i++) {
	stats[i].len = rt2x00dev->tx[i].length;
	stats[i].limit = rt2x00dev->tx[i].limit;
	stats[i].count = rt2x00dev->tx[i].count;
	}

	return 0;
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_get_tx_stats);

	void rt2x00mac_bss_info_changed(struct ieee80211_hw *hw,
	struct ieee80211_vif *vif,
	struct ieee80211_bss_conf *bss_conf,
	u32 changes)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct rt2x00_intf *intf = vif_to_intf(vif);
	unsigned int delayed = 0;

	/*
	* When the association status has changed we must reset the link
	* tuner counter. This is because some drivers determine if they
	* should perform link tuning based on the number of seconds
	* while associated or not associated.
	*/
	if (changes & BSS_CHANGED_ASSOC) {
	rt2x00dev->link.count = 0;

	if (bss_conf->assoc)
	rt2x00dev->intf_associated++;
	else
	rt2x00dev->intf_associated--;

	if (!test_bit(DRIVER_REQUIRE_SCHEDULED, &rt2x00dev->flags))
	rt2x00leds_led_assoc(rt2x00dev,
	!!rt2x00dev->intf_associated);
	else
	delayed \|= DELAYED_LED_ASSOC;
	}

	/*
	* When the erp information has changed, we should perform
	* additional configuration steps. For all other changes we are done.
	*/
	if (changes & (BSS_CHANGED_ERP_PREAMBLE \| BSS_CHANGED_ERP_CTS_PROT)) {
	if (!test_bit(DRIVER_REQUIRE_SCHEDULED, &rt2x00dev->flags))
	rt2x00lib_config_erp(rt2x00dev, intf, bss_conf);
	else
	delayed \|= DELAYED_CONFIG_ERP;
	}

	spin_lock(&intf->lock);
	memcpy(&intf->conf, bss_conf, sizeof(*bss_conf));
	if (delayed) {
	intf->delayed_flags \|= delayed;
	schedule_work(&rt2x00dev->intf_work);
	}
	spin_unlock(&intf->lock);
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_bss_info_changed);

	int rt2x00mac_conf_tx(struct ieee80211_hw *hw, u16 queue_idx,
	const struct ieee80211_tx_queue_params *params)
	{
	struct rt2x00_dev *rt2x00dev = hw->priv;
	struct data_queue *queue;

	queue = rt2x00queue_get_queue(rt2x00dev, queue_idx);
	if (unlikely(!queue))
	return -EINVAL;

	/*
	* The passed variables are stored as real value ((2^n)-1).
	* Ralink registers require to know the bit number 'n'.
	*/
	if (params->cw_min > 0)
	queue->cw_min = fls(params->cw_min);
	else
	queue->cw_min = 5; /* cw_min: 2^5 = 32. */

	if (params->cw_max > 0)
	queue->cw_max = fls(params->cw_max);
	else
	queue->cw_max = 10; /* cw_min: 2^10 = 1024. */

	queue->aifs = params->aifs;

	INFO(rt2x00dev,
	"Configured TX queue %d - CWmin: %d, CWmax: %d, Aifs: %d.\n",
	queue_idx, queue->cw_min, queue->cw_max, queue->aifs);

	return 0;
	}
	EXPORT_SYMBOL_GPL(rt2x00mac_conf_tx);